A thin double-layer multiple parallel-arranged inhomogeneous microperforated panel absorber for wideband low-frequency sound absorption

Rafique, Faisal; Wu, Jiu Hui; Waqas, Muhammad; Xu, Liang; Ma, Fuyin

doi:10.1007/s40430-021-03327-4

Cited by 9 publications

(4 citation statements)

References 22 publications

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“…Prototype 1, consisting of one layer composed of four different MPPs facing different cavities, showed a wider absorption bandwidth in the low-mid frequency spectrum (α ≥ 0.5 from 300 to 1250 Hz). Despite some discrepancies, which literature has shown to be quite common in those complex structures [49,50,59], the results indicate a broadening of the absorption coefficient curve because of the multiple resonance peaks each panel introduces. Prototype 2 was composed of two layers having different parallel-arranged MPPs cascaded one after the other, with a distance (D1) in between and various partitioned cavities (D2) after the second layer.…”

Section: Discussionmentioning

confidence: 54%

“…These structures can be an alternative to conventional absorbing materials in architectural applications to attenuate a broader range of frequencies. Many studies [47,49,50,59] have investigated different combinations to address the narrow bandwidth of MPPs, but to the authors' knowledge, none have continued to assess the performance of those materials in architectural applications.…”

Section: Discussionmentioning

confidence: 99%

“…Those innovations have set the ground for the realization of complex structures that exhibit acoustic properties not found in nature [26]. Moreover, the hybrid serial-parallel MPP structures designed on polymers [45][46][47][48][49][50] have shown that the correct combination of multiple parameters may achieve a more efficient and wideband sound absorption.…”

Section: Introductionmentioning

confidence: 99%

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Investigating the Potential of Transparent Parallel-Arranged Micro-Perforated Panels (MPPs) as Sound Absorbers in Classrooms

Fasllija

Yılmazer

2023

IJERPH

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Acoustic deficiencies due to lack of absorption in indoor spaces may sometime render significant buildings unfit for their purpose, especially the ones used as speech auditoria. This study investigates the potential of designing wideband acoustic absorbers composed of parallel-arranged micro-perforated panels (MPPs), known as efficient absorbers that do not need any other fibrous/porous material to have a high absorptive performance. It aims to integrate architectural trends such as transparency and the use of raw materials with acoustical constraints to ensure optimal indoor acoustic conditions. It proposes a structure composed of four parallel-arranged MPPs, which have been theoretically modelled using the electrical Equivalent Circuit Model (ECM) and implemented on an acrylic prototype using recent techniques such as CNC machining tools. The resulting samples are experimentally analysed for their absorption efficiency through the ISO-10534-2 method in an impedance tube. The results show that the prediction model and the experimental data are in good agreement. Afterward, the investigation focuses on applying the most absorptive MPP structure in a classroom without acoustic treatment through numerical simulations in ODEON 16 Acoustics Software. When the proposed material is installed as a wall panel, the results show an improvement toward optimum values in Reverberation Time (RT30) and Speech Transmission Index (STI).

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Section: Discussionmentioning

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigating the Potential of Transparent Parallel-Arranged Micro-Perforated Panels (MPPs) as Sound Absorbers in Classrooms

Fasllija

Yılmazer

2023

IJERPH

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“…This work proposed an acoustic composite structure capable of high-efficiency sound absorption (>90%) within a 230 Hz to 470 Hz frequency range. The composite sound-absorbing structure consists of the parallel-arranged inhomogeneous microperforated panel (iMPP) [40][41][42][43] backed with spider-web designed cavities of different shapes, while the electrical equivalent circuit approach (ECM) is employed to examine its sound absorption properties and processes, it is also utilized to build a mathematical model and FEM-based simulation. The performance of the composite structure was validated by using an impedance tube for normal incidence.…”

Section: Introductionmentioning

confidence: 99%

Extremely effective broadband low-frequency sound absorption with inhomogeneous micro-perforated panel (iMPP) backed with spider-web designed cavities

Rafique

Naqvi

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part L:

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Low-frequency wideband noise reduction has posed a significant problem to the scientific and technical communities in recent years. A single layer of a parallel-arranged inhomogeneous micro-perforated panel (iMPP) coupled with spider-web designed cavities is offered as a composite acoustic structure in this paper. Three different spider-web shapes have been designed and studied, i.e. circular, octagonal, and square. By controlling the different inhomogeneous patterns, perforation ratio, the thickness of iMPP, and back cavity depths, a broader multipeak low-frequency sound-absorbing performance equivalent to different resonant frequencies can be achieved. To anticipate the sound absorption coefficient of the new design, both theoretical analysis and finite-element method (FEM) simulation are executed. The predicted and FEM simulation sound absorption results of the new composite structure are verified in the experimental investigation using a square-designed sound impedance tube. By a subwavelength thickness of just 100 mm, a highly effective low-frequency broadband sound-absorbing composite structure is successfully attained by integrating many inhomogeneous MPP unit cells supported with spider-web-designed cavities. The average sound absorption coefficient is over 90% ( α = 0.94) within the bandgap of 230 Hz to 470 Hz. Compared to traditional sound-absorbing materials, the composite structure comprises inhomogeneous MPP coupled with spider-web-designed cavities, which may provide good absorption performance while maintaining a modest and robust construction for active low-frequency noise suppression.

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Ultra-Low-Frequency Broadband Sound Absorption Characteristics of an Acoustic Metasurface with Pie-Sliced Unit Cells

et al. 2023

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A thin double-layer multiple parallel-arranged inhomogeneous microperforated panel absorber for wideband low-frequency sound absorption

Cited by 9 publications

References 22 publications

Investigating the Potential of Transparent Parallel-Arranged Micro-Perforated Panels (MPPs) as Sound Absorbers in Classrooms

Investigating the Potential of Transparent Parallel-Arranged Micro-Perforated Panels (MPPs) as Sound Absorbers in Classrooms

Extremely effective broadband low-frequency sound absorption with inhomogeneous micro-perforated panel (iMPP) backed with spider-web designed cavities

Ultra-Low-Frequency Broadband Sound Absorption Characteristics of an Acoustic Metasurface with Pie-Sliced Unit Cells

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